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<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> foo = <span class="hljs-string">&apos;bar&apos;</span>;
<span class="hljs-keyword">const</span> baz = {foo};
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<p>&#x9664;&#x4E86;&#x5C5E;&#x6027;&#x7B80;&#x5199;&#xFF0C;&#x65B9;&#x6CD5;&#x4E5F;&#x53EF;&#x4EE5;&#x7B80;&#x5199;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> o = {
  method() {
    <span class="hljs-keyword">return</span> <span class="hljs-string">&quot;Hello!&quot;</span>;
  }
};

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E;</span>

<span class="hljs-keyword">const</span> o = {
  method: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params"></span>) </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-string">&quot;Hello!&quot;</span>;
  }
};
</code></pre>
<h3 id="&#x5C5E;&#x6027;&#x540D;&#x8868;&#x8FBE;&#x5F0F;">&#x5C5E;&#x6027;&#x540D;&#x8868;&#x8FBE;&#x5F0F;</h3>
<p>JavaScript &#x5B9A;&#x4E49;&#x5BF9;&#x8C61;&#x7684;&#x5C5E;&#x6027;&#xFF0C;&#x6709;&#x4E24;&#x79CD;&#x65B9;&#x6CD5;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// &#x65B9;&#x6CD5;&#x4E00;</span>
obj.foo = <span class="hljs-literal">true</span>;

<span class="hljs-comment">// &#x65B9;&#x6CD5;&#x4E8C;</span>
obj[<span class="hljs-string">&apos;a&apos;</span> + <span class="hljs-string">&apos;bc&apos;</span>] = <span class="hljs-number">123</span>;
</code></pre>
<h3 id="objectis">Object.is()</h3>
<p>ES5 &#x6BD4;&#x8F83;&#x4E24;&#x4E2A;&#x503C;&#x662F;&#x5426;&#x76F8;&#x7B49;&#xFF0C;&#x53EA;&#x6709;&#x4E24;&#x4E2A;&#x8FD0;&#x7B97;&#x7B26;&#xFF1A;&#x76F8;&#x7B49;&#x8FD0;&#x7B97;&#x7B26;&#xFF08;<code>==</code>&#xFF09;&#x548C;&#x4E25;&#x683C;&#x76F8;&#x7B49;&#x8FD0;&#x7B97;&#x7B26;&#xFF08;<code>===</code>&#xFF09;&#x3002;&#x5B83;&#x4EEC;&#x90FD;&#x6709;&#x7F3A;&#x70B9;&#xFF0C;&#x524D;&#x8005;&#x4F1A;&#x81EA;&#x52A8;&#x8F6C;&#x6362;&#x6570;&#x636E;&#x7C7B;&#x578B;&#xFF0C;&#x540E;&#x8005;&#x7684;<code>NaN</code>&#x4E0D;&#x7B49;&#x4E8E;&#x81EA;&#x8EAB;&#xFF0C;&#x4EE5;&#x53CA;<code>+0</code>&#x7B49;&#x4E8E;<code>-0</code>&#x3002;JavaScript &#x7F3A;&#x4E4F;&#x4E00;&#x79CD;&#x8FD0;&#x7B97;&#xFF0C;&#x5728;&#x6240;&#x6709;&#x73AF;&#x5883;&#x4E2D;&#xFF0C;&#x53EA;&#x8981;&#x4E24;&#x4E2A;&#x503C;&#x662F;&#x4E00;&#x6837;&#x7684;&#xFF0C;&#x5B83;&#x4EEC;&#x5C31;&#x5E94;&#x8BE5;&#x76F8;&#x7B49;&#x3002;</p>
<p>ES6 &#x63D0;&#x51FA;&#x201C;Same-value equality&#x201D;&#xFF08;&#x540C;&#x503C;&#x76F8;&#x7B49;&#xFF09;&#x7B97;&#x6CD5;&#xFF0C;&#x7528;&#x6765;&#x89E3;&#x51B3;&#x8FD9;&#x4E2A;&#x95EE;&#x9898;&#x3002;<code>Object.is</code>&#x5C31;&#x662F;&#x90E8;&#x7F72;&#x8FD9;&#x4E2A;&#x7B97;&#x6CD5;&#x7684;&#x65B0;&#x65B9;&#x6CD5;&#x3002;&#x5B83;&#x7528;&#x6765;&#x6BD4;&#x8F83;&#x4E24;&#x4E2A;&#x503C;&#x662F;&#x5426;&#x4E25;&#x683C;&#x76F8;&#x7B49;&#xFF0C;&#x4E0E;&#x4E25;&#x683C;&#x6BD4;&#x8F83;&#x8FD0;&#x7B97;&#x7B26;&#xFF08;===&#xFF09;&#x7684;&#x884C;&#x4E3A;&#x57FA;&#x672C;&#x4E00;&#x81F4;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-built_in">Object</span>.is(<span class="hljs-string">&apos;foo&apos;</span>, <span class="hljs-string">&apos;foo&apos;</span>)
<span class="hljs-comment">// true</span>
<span class="hljs-built_in">Object</span>.is({}, {})
<span class="hljs-comment">// false</span>
</code></pre>
<p>&#x4E0D;&#x540C;&#x4E4B;&#x5904;&#x53EA;&#x6709;&#x4E24;&#x4E2A;&#xFF1A;&#x4E00;&#x662F;<code>+0</code>&#x4E0D;&#x7B49;&#x4E8E;<code>-0</code>&#xFF0C;&#x4E8C;&#x662F;<code>NaN</code>&#x7B49;&#x4E8E;&#x81EA;&#x8EAB;&#x3002;</p>
<pre><code class="lang-javascript">+<span class="hljs-number">0</span> === <span class="hljs-number">-0</span> <span class="hljs-comment">//true</span>
<span class="hljs-literal">NaN</span> === <span class="hljs-literal">NaN</span> <span class="hljs-comment">// false</span>

<span class="hljs-built_in">Object</span>.is(+<span class="hljs-number">0</span>, <span class="hljs-number">-0</span>) <span class="hljs-comment">// false</span>
<span class="hljs-built_in">Object</span>.is(<span class="hljs-literal">NaN</span>, <span class="hljs-literal">NaN</span>) <span class="hljs-comment">// true</span>
</code></pre>
<h3 id="objectassign">Object.assign()</h3>
<p><code>Object.assign</code>&#x65B9;&#x6CD5;&#x7528;&#x4E8E;&#x5BF9;&#x8C61;&#x7684;&#x5408;&#x5E76;&#xFF0C;&#x5C06;&#x6E90;&#x5BF9;&#x8C61;&#xFF08;source&#xFF09;&#x7684;&#x6240;&#x6709;&#x53EF;&#x679A;&#x4E3E;&#x5C5E;&#x6027;&#xFF0C;&#x590D;&#x5236;&#x5230;&#x76EE;&#x6807;&#x5BF9;&#x8C61;&#xFF08;target&#xFF09;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> target = { a: <span class="hljs-number">1</span> };

<span class="hljs-keyword">const</span> source1 = { b: <span class="hljs-number">2</span> };
<span class="hljs-keyword">const</span> source2 = { c: <span class="hljs-number">3</span> };

<span class="hljs-built_in">Object</span>.assign(target, source1, source2);
target <span class="hljs-comment">// {a:1, b:2, c:3}</span>
</code></pre>
<p><code>Object.assign</code>&#x65B9;&#x6CD5;&#x7684;&#x7B2C;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#x662F;&#x76EE;&#x6807;&#x5BF9;&#x8C61;&#xFF0C;&#x540E;&#x9762;&#x7684;&#x53C2;&#x6570;&#x90FD;&#x662F;&#x6E90;&#x5BF9;&#x8C61;&#x3002;</p>
<p>&#x6CE8;&#x610F;&#xFF0C;&#x5982;&#x679C;&#x76EE;&#x6807;&#x5BF9;&#x8C61;&#x4E0E;&#x6E90;&#x5BF9;&#x8C61;&#x6709;&#x540C;&#x540D;&#x5C5E;&#x6027;&#xFF0C;&#x6216;&#x591A;&#x4E2A;&#x6E90;&#x5BF9;&#x8C61;&#x6709;&#x540C;&#x540D;&#x5C5E;&#x6027;&#xFF0C;&#x5219;&#x540E;&#x9762;&#x7684;&#x5C5E;&#x6027;&#x4F1A;&#x8986;&#x76D6;&#x524D;&#x9762;&#x7684;&#x5C5E;&#x6027;&#x3002;</p>
<p><font color="red">&#x6CE8;&#x610F;&#x70B9;</font>,<code>Object.assign</code>&#x65B9;&#x6CD5;&#x5B9E;&#x884C;&#x7684;&#x662F;&#x6D45;&#x62F7;&#x8D1D;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x6DF1;&#x62F7;&#x8D1D;&#x3002;</p>
<p>&#x5BF9;&#x4E8E;&#x8FD9;&#x79CD;&#x5D4C;&#x5957;&#x7684;&#x5BF9;&#x8C61;&#xFF0C;&#x4E00;&#x65E6;&#x9047;&#x5230;&#x540C;&#x540D;&#x5C5E;&#x6027;&#xFF0C;<code>Object.assign</code>&#x7684;&#x5904;&#x7406;&#x65B9;&#x6CD5;&#x662F;&#x66FF;&#x6362;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x6DFB;&#x52A0;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> target = { a: { b: <span class="hljs-string">&apos;c&apos;</span>, d: <span class="hljs-string">&apos;e&apos;</span> } }
<span class="hljs-keyword">const</span> source = { a: { b: <span class="hljs-string">&apos;hello&apos;</span> } }
<span class="hljs-built_in">Object</span>.assign(target, source)
<span class="hljs-comment">// { a: { b: &apos;hello&apos; } }</span>
</code></pre>
<h3 id="&#x5BF9;&#x8C61;&#x7684;&#x6269;&#x5C55;&#x8FD0;&#x7B97;&#x7B26;">&#x5BF9;&#x8C61;&#x7684;&#x6269;&#x5C55;&#x8FD0;&#x7B97;&#x7B26;</h3>
<p>&#x4E4B;&#x524D;&#x4ECB;&#x7ECD;&#x8FC7;&#x6570;&#x7EC4;&#x7684;&#x6269;&#x5C55;&#x8FD0;&#x7B97;&#x7B26;,&#x540C;&#x7406;&#x5BF9;&#x8C61;&#x7684;&#x6269;&#x5C55;&#x8FD0;&#x7B97;&#x7B26;&#x4E5F;&#x4E00;&#x6837;&#x3002;</p>
<pre><code class="lang-js"><span class="hljs-keyword">const</span> data = {title: <span class="hljs-string">&apos;origin&apos;</span>};
<span class="hljs-keyword">const</span> newData = {...data,other: <span class="hljs-string">&apos;none&apos;</span>};
<span class="hljs-comment">// { title: &apos;origin&apos;, other: &apos;none&apos;}</span>
<span class="hljs-keyword">const</span> newData2 = {...data, title: <span class="hljs-string">&apos;newTitle&apos;</span>};
<span class="hljs-comment">// { title: &apos;newTitle&apos; } &#x53EF;&#x4EE5;&#x7406;&#x89E3;&#x4E3A; Object.assign(data,{title: &apos;newTitle&apos;});</span>
</code></pre>

                                
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